Anodically Triggered Aldehyde Cation Autocatalysis for Alkylation of Heteroarenes

Friedel-Crafts arylation of aldehydes with indoles utilizing arylazo sulfones as the photoacid generator

A versatile, inexpensive and sustainable protocol for the preparation of valuable bis-indolyl methanes via visible light-mediated, metal-free Friedel-Crafts arylation has been developed. The procedure, that exploits the peculiar behavior of arylazo sulfones as non-ionic photoacid generators (PAGs), was applied to the conversion of a variety of aliphatic and aromatic aldehydes into diarylmethanes in good to highly satisfactory yields, employing a low-catalyst loading (0.5 mol%) and irradiation at 456 nm.

Electrochemically enhanced deoxygenative cross-coupling of aryl ketones with heteroarenes through in situ generated benzyl carbocations

Triflic acids/silanes as cooperative reductants enable the convenient transformation of CO bonds through a multistep reaction pathway in one pot. Electrolysis of the acidic reaction mixture significantly improved carbonyl reduction and thus facilitated the generation of benzyl carbocations, which show high reactivity towards electron-rich heteroarenes for C-C bond formation.